scg

scg is a Swift-based command line tool that inspects your current Git repository, summarizes the staged and unstaged changes, and generates a commit message proposal with Apple's on-device generative model. The goal is to keep human-in-the-loop Git commits fast, consistent, and privacy-preserving by relying on system-provided AI capabilities instead of cloud services.

CommitGen.mov

Features

• Detects dirty Git worktrees and extracts concise change context
• Crafts commit message drafts with Apple's onboard generative APIs
• Provides an interactive acceptance/edit flow before writing the commit
• Persists CLI defaults with an interactive config command
• Respects local-only privacy requirements (no network calls)

Project Status

The CLI currently supports end-to-end commit generation, including Git inspection, AI-assisted drafting, interactive editing, optional auto-staging/committing, and persistent configuration defaults. Advanced batching for huge diffs is available and continues to evolve based on real-world feedback.

Prerequisites

• macOS 26 (Sequoia) or later with the Apple Intelligence feature set enabled
• Xcode 26 (or newer) with the command line tools installed (xcode-select --install)
• Swift 6 toolchain (ships with Xcode 26)
• Git 2.40+ available on PATH
• Full Disk Access enabled for the Terminal (or your preferred shell) so the FoundationModels framework can initialize properly

Installation

Option 1: Homebrew (Recommended)

brew tap Iron-Ham/swift-commit-gen
brew install scg

Or install directly without tapping:

brew install Iron-Ham/swift-commit-gen/scg

Option 2: Install Script

1. Clone the repository:

   git clone https://github.com/Iron-Ham/swift-commit-gen.git
   cd swift-commit-gen

2. Run the bundled install script (installs into ~/.local/bin by default):

   Scripts/install.sh

   Pass a custom destination as the first argument to install elsewhere, e.g. Scripts/install.sh /usr/local/bin.

Option 3: Manual Build

If you prefer manual installation, build and copy the binary yourself:

git clone https://github.com/Iron-Ham/swift-commit-gen.git
cd swift-commit-gen
swift build -c release
install -d "$HOME/.local/bin"
install .build/release/scg "$HOME/.local/bin/"

Add export PATH="$HOME/.local/bin:$PATH" to your shell profile if needed.

First-Run Notes

• The first invocation may prompt for Apple Intelligence access; approve the request in System Settings → Privacy & Security → Apple Intelligence.
• If scg reports that the model is unavailable, ensure Apple Intelligence is enabled and the device satisfies the on-device requirements.

Usage

From the root of a Git repository with pending changes:

swift run scg generate

Or, after installation:

scg generate

Command

You can invoke the tool either with the explicit generate subcommand or omit it because generate is the default subcommand.

Primary (shorter) form:

scg [OPTIONS]

Equivalent explicit form:

scg generate [OPTIONS]

Generation Flow

1. Inspect repository (staged changes only)
2. Summarize diff and plan prompt batches if large
3. Request draft commit message from on-device model
4. Interactive review loop (accept / edit / regenerate)
5. Optional auto-commit

Flags & Options

Flag	Short	Description	Default	Notes
--format <text|json>		Output format for the draft	text	JSON skips the interactive review loop.
--commit / --no-commit		Apply the accepted draft with git commit	On	--no-commit leaves the draft uncommitted.
--stage		Stage all pending changes (including untracked) before drafting	Off	Equivalent to git add --all before generation.
--no-stage		Disable staging, even if configured as a default	-	Wins over stored auto-stage preferences.
--verbose	-v	Emit detailed prompt diagnostics and debug lines	Off	Shows [DEBUG] messages. Overrides --quiet.
--no-verbose		Force verbose output off, even if configured as default	-	Useful for scripts overriding stored settings.
--quiet	-q	Suppress routine info lines	Off	Hides [INFO] but keeps [NOTICE], warnings, errors. Ignored if --verbose is present.
--no-quiet		Ensure quiet mode is disabled, even if configured	-	Helpful when scripts need full output.
--single-file		Analyze each file independently and then combine per-file drafts	Off	Sends a larger diff slice per file, useful when you need high-fidelity summaries.

Verbosity Levels

The logger uses distinct levels to balance clarity and noise:

• [ERROR]: Fatal issues preventing progress
• [WARNING]: Non-fatal problems or user action advisories
• [NOTICE]: Essential workflow milestones (always shown, even with --quiet)
• [INFO]: Routine progress details (hidden with --quiet)
• [DEBUG]: High-volume diagnostics (only with --verbose)

Precedence: --verbose > --quiet. Supplying both yields verbose output.

Examples

Generate and interactively accept a draft (default):

scg

Auto-commit the already staged changes:

scg --commit

Stage everything first, then show verbose diagnostics:

scg --stage --verbose

Minimal essential output (quiet mode) but still commit:

scg --quiet --commit

Produce machine-readable JSON (no interactive loop):

scg --format json

Request high-fidelity per-file drafts before they are combined:

scg --single-file

Configuration Defaults

Use the config subcommand to inspect or update stored defaults. Running it with no flags opens an interactive, colorized editor that walks through each preference:

scg config

Available options:

Flag	Description
--show	Print the current configuration without making changes.
--auto-stage-if-clean <true|false>	Persist whether generate should stage all files when nothing is staged.
--clear-auto-stage	Remove the stored auto-stage preference.
--verbose <true|false>	Set the default verbose logging preference.
--clear-verbose	Remove the stored verbose preference.
--quiet <true|false>	Set the default quiet logging preference.
--clear-quiet	Remove the stored quiet preference.

When no options are provided, the command detects whether the terminal is interactive and presents guided prompts with recommended defaults highlighted. Stored settings live in ~/Library/Application Support/scg/config.json.

Help

For a full list of commands:

scg help # or scg -h

For help with a specific command, such as generate:

scg help generate # or scg generate -h